Help!!!!

[RadoAds 0]

Just replaced rear disks, rear pads and rear calipers on a Seat Leon 1.4, (same as golf) and now theres no pressure on brake pedal, with engine off I can bleed the brakes up and get a half decent pedal but as soon as I start the engine i can move the pedal up and down with my hand tried clamping one off and bleeding the other but with same result, any ideas anyone, anybody had the same prob

 

The car failed its mot on low service effort, both calipers had siezed so they had to be replaced, pads were shot and disks werent too good either so I dont want to have to fork out for a master cylinder if for some reason Ive reversed the seals especially as I dont think it is that

 

HELP!! :(

[VR6 0]

A more descriptive thread title might mean that the right people look at the problem for you :)

[Supercharged 2]

Hmmm - you changed them and bled them with the handbrake off I assume...

 

Does it have ABS, does it have a rear brake bias valve / compensator?

[RadoAds 0]

Yup ABS, rear brake compensator and was bled with the wheels down on the floor so it was open, handbrake off, fluid is being passed well when bleeding, pedal feels ok when engine off but as soon as the engine is started pedal becomes slack, Ive been in the motor trade for 7 years and am an MOT tester (or was should I say) so its not something stupid that Ive done wrong, Ive double checked everything and Ive changed dozens of mark 3 rear calipers in the past without a hitch. Its just the first time its ever happened and just thought someone else might have had the same prob.

[bcstudent 0]

I've never had to bleed the brakes on an ABS-equipped car before but I can half remember reading that they should be done with the ignition on. Is that true?

[RadoAds 0]

Sorted it, had to bleed from the master cylinder dont know how air got up there, the only thing I can put it down to is that the rear calipers were seized solid and the brake pads had almost melted onto the disks so could be that the fluid had boiled and created air in the system, but when I test drove it before the job the pedal felt fine although low on effort, oh well job sorted.

[bcstudent 0]

So, just for the record, ABS brake bleeding with ignition on or off? I have no idea what goes on inside an ABS pump.

[RadoAds 0]

I ended up doing with it on, but then again Ive done plenty with them off with no adverse effects

[Supercharged 2]

It only needs to beon for US models (thats why it states it in the Bentley)

[2cc 0]

Yep, RW1 has posted the definitive bleeding routines quite a number of times.....